Submersible sump pump control



Aug. 27, 1957 E; J. SCHAEFER SUBMERSIBLE SUMP PUMP CONTROL Filed Sept. 7, 1955 1g 3g A 2 41 Unite This invention relates generally to sump pumps and more particularly to a novel control means for a sump pump of the submersible type.

In my prior Patents Nos. 2,662,206, of December 8, 1953, and 2,704,346, of March 15, 1956, I have described and claimed a sump pump arrangement wherein the electric motor for the pump unit is of the submersible type and is positioned immediately adjacent the pump unit. The motor is rendered submersible by means of a shell or enclosure which includes a flexible diaphragm means adapted to actuate a control switch for the motor in response to changes of water level outside the enclosure. Preferably, the diaphragm means constitutes an end portion of the motor enclosure and, in addition, the diaphragm means is preferably arranged so that the entire motor enclosure functions as a float control.

With the sump pump arrangement of my aforementioned prior patents the pump is automatically turned on when the Water in the sump reaches a predetermined maximum level sufficient to deflect the diaphragm means and actuate the control switch. The pump continues to operate until the water in the sump recedes to a minimum level, such that the head or" water in the sump is insuflicient to deflect the diaphragm means whereupon the control switch returns to its normal position. In the event that it is desirable to pump the sump substantially dry, i. e. below the minimum effective level for actuating the diaphragm means, an auxiliary control device may be used such as disclosed in my prior Patent No. 2,625,107 of January 13, 1953. The auxiliary control device disclosed therein comprises a pressure-transmitting means such as an open jet tube or an expansible bellows connected to the discharge side of the pump and disposed in operative relation adjacent the pump diaphragm control means for actuating the latter independently of the liquid level outside the motor enclosure. Thus, the pump is kept in operation until it loses suction when the sump is substantially empty.

The present invention relates to certain improvements in a pump-to-dryness sump pump control of the general type described in my prior Patent 2,625,107 which utilizes pump discharge pressure for control purposes. As hereinafter described in detail, I have found that there is an optimum location for the pressure transmitting device relative to the pump volute in order to obtain most eifec: tive shut-off of the pump under different operating conditions. Moreover, I have now devised an improved and more advantageous structure for the pressure transmitting auxiliary control device.

Accordingly, a primary object of my invention is to provide a novel and improved control means for a sump pump which insures continued operation of the pump until it begins to draw air.

A further object of the invention is to provide novel means in a float controlled submersible sump pump for more effectively utilizing the discharge pressure of the pump. to prolong the operation of the pump until the tates Pat ice pump loses suction and thereafter permitting rapid shut- 011 of the pump.

Another object of the invention is to provide an improved submersible sump pump arrangement including main control means for the motor and an auxiliary control device cooperable with the main control means to insure operation of the pump until it loses suction and having a certain preferred location on the pump volute for obtaining rapid shut-ofi of the pump when it loses suction.

An additional object of the invention is to provide a novel arrangement as described in the preceding object while utilizing only a single pressure responsive member.

Other objects and advantages of the invention will become evident from the subsequent detailed description taken in conjunction with the accompanying drawing wherein:

Fig. 1 is a vertical sectional view of a sump pump unit illustrating one specific embodiment of my invention;

Fig. 2 is an enlarged fragmentary sectional view taken along the line 22 of Fig. 1;

Fig. 3 is a transverse sectional view of the unit as taken along the line 3-3 of Fig. 1; and

Fig. 4 is a fragmentary sectional view showing a modification of the invention.

Referring first to Figs. 1-3 of the drawings, the invention comprises an electric motor 5 of a conventional type having a rotor'shaft 6 depending therefrom. Disposed below the motor 5 and immediately adjacent thereto is a centrifugal pump unit 7 of a conventional type having a casing 8 with an inlet 9, a discharge volute 10, and a discharge outlet 11 from the volute. The pump impeller, indicated at 12, is secured at the lower end of the shaft 6 and the latter is provided with a suitable rotating seal (not shown) to prevent entry of water to the motor through the shaft outlet.

Surrounding the motor 5 for rendering the latter submersible is an enclosure, indicated generally at 14, which comprises a cylindrical body portion 16 supported on the motor 5 by means of a pair of substantially identical upper and lower end portions designated generally by the reference numeral 17. The body portion 16 is preferably formed from relatively thin corrosion-resistant metal such as stainless steel.

Each of the end portions 17 of the enclosure 14 comprises a deflectable diaphragm means including a relatively thin annular element 18 which may be of metal. The outer marginal or peripheral edge of each of the elements 18 is turned inwardly toward the motor 5 to provide a flange or rim 19 which is rigidly secured and sealed, preferably by welding, to the inner periphery of the body portion 16 of the enclosure 14. The inner marginal of peripheral edge of each element 18 is turned axially outward away from the motor 5, as at 21, and is flexibly attached to the motor 5 by means of an annular connecting collar, indicated generally at 22. The collars 22 are preferably formed from a resilient material such as rubber or the like and are generally U-shaped in crosssection. Thus, each of the collars 22 is formed with rela tively heavy concentric inner and outer ring portions 23 and 24, respectively, which are interconnected adjacent their outermost edges by a relatively thin integral connecting portion 26. The collars 22 are secured to the elements 13 by means of the outwardly turned edges 21 of the later which may be flared outwardly to a slight extent in order to provide a snug engagement with the inner periphery of the collar portions 24. The inner portions 23 of the collars 22 fit snugly around the upper and lower hub portions of the motor 5, as indicated at 27 and 28, respectively.

Thus, the combination of the enclosure 14 with the upper and lower end portions or diaphragm means 1! forms a water-tight casing which renders the motor 5 submersible and at the same time constitutes a float which is free for limited movement in a vertical direction upon flexing of the connecting portions 26 of the collars 22 as hereinafter described.

For automatically regulating the operation of the motor 5, a control switch 29 having a depressible spring-pressed operating member or button 31 is mounted adjacent the upper portion of the motor 5 with the operating button 31 facing the upper annular element 13 in operative relation therewith. The switch 29 is of a type in which only a relatively slight movement of the operating button 31, e. g. of an inch, is suflicient to cause the actuation of the switch between on and off positions. It will be understood that the enclosure 14, which is sealed to the upper and lower ends of the motor 5 by the end diaphragm means 17, will function as a float when the motor and pump unit are disposed at the bottom of a sump. Thus, as the water level in the sump rises, the enclosure 14 containing trapped air is lifted upwardly relative to the motor 5 by the buoyant effect of the water, the flexible connecting portions 2s of the collars 22 permitting this upward movement. Upon upward movement of the enclosure 14, the upper element 13 moves away from the operating button 31 permitting the lattter to move outwardly whereby to complete the electrical circuit for the motor 5 and thereby start the pump '7 in operation. Similarly, as the water level in the sump recedes during operating of the pump 7, the weight of the enclosure 14 causes the latter to move downwardly whereupon the upper element 18 engages the switch button 31 and depresses the latter to shut off the motor.

Means comprising a bridge member and guide screws (not shown in detail in the drawing) is provided at the upper end of the motor for guiding and limiting the vertical movement of the float enclosure 14 relative to the motor 5. Details of this structure are described fully in my prior Patent No. 2,662,206 and need not be repeated here. A dome-shaped cover 32 is detachably mounted over the upper end of the device with the depending skirt portion thereof. fitting over and frictionally engaging the upper end of the body 16 of the enclosure 14, as at 33. A handle 34.- is fastened to the cover 32 for raising and lowering the entire unit. Means (not shown) comprising suitable electric wires is also provided for conducting electric current to the switch 2? and the motor 5.

As the motor 5 heats up during operation, the temperature of the air trapped inside of the enclosure 14 may vary much as C. Under such circumstances it is desirable to compensate for varying air pressure in order to avoid the possibility that an increase in air pressure inside the enclosure might cause movement of the enclosure relative to the motor and thereby effect the operation of the device independently of any change of water level. However, the provision of substantially identical diaphragm means 37, i. e. diaphragm means having substantially the same exposed areas, at the top and bottom of the cylindrical portion 16 of the enclosure 14 balances out the effect of varying air pressure within the enclosure and leaves the upward and downward movement of the enclosure 14 dependent solely upon external pressure. In other words, even if the pressure of the air surrounding the motor 5 and within the enclosure 14 should increase, the net force tending to move the enclosure 14 relative to the motor 5 will be zero because the force acting against the upper diaphragm means 17 tending to move the enclosure M up- Wardly will be counteracted by a substantially identical force acti against the lower diaphragm means 17 tending to move the enclosure 14 downwardly. The cover 32 is provided with suitable means (not shown) for permitting drainage of Water from the space between the cover 32 and the upper diaphragm means 17 and also for preventing air from being trapped in this space.

From the foregoing description it will be seen that the main control means for the sump pump unit comprises the diaphragm means 17 which are deflectable in response to changes in liquid level outside the enclosure 14 for actuating the control switch 29. With this main control means alone the pump shuts off at a predetermined minimum water level in the sump which corresponds to the level at which the buoyant or lifting effect is lost. Such operation is satisfactory in many cases, but in other situations it may be desirable to have the sump emptied to substantial dryness.

in my prior Patent No. 2,625,107 an auxiliary control means is provided which utilizes the fluid discharge pressure of the pump for independently actuating the motor enclosure and the control switch whereby operation of the pump is prolonged until the sump is substantially empty at which point the pump loses suction. However, I have new discovered that in order to obtain most effective and consistent results with an auxiliary control of this general character which depends on fluid discharge pressure from a centrifugal pump, it is necessary that the auxiliary control device have a rather specific location with respect to the volute of the pump chamber or casing. From experimental observations of the liquid pressure at different locations in the volute of a centrifugal pump, I have discovered that at a region approximately diametrically oppo site from the discharge outlet of the volute the pressure in the volute is at a minimum when the pump loses suction. Ideally, it would be desirable to locate the discharge pressure tap-off for the auxiliary control at a point at which the pressure drops to zero when the pump loses suction. However, as a practical matter, I have found that there is a certain residual pressure in the volute even at the break suction point and the magnitude of this residual pressure varies somewhat dependent upon the length of the discharge pipe from the sump and the static head against which the pump operates. However, the residual pressure in the pump volute when the pump loses suction is at a minimum approximately from the discharge outlet of the volute, and furthermore the differential between volute pressure during normal running and the residual pressure at the time the pump loses suction is at a maximum at the aforementioned location, namely, approximately 180 fro-m the discharge outlet.

By taking advantage of the foregoing situation and locating the auxiliary control pressure tap-off at the specified optimum point in the pump volute, I am able to provide a highly effective device which does not require special calibration for a variable residual pressure which is dependent upon the back pressure or static head against which the pump happens to be operating in any given installation. According to the present invention, the auxiliary control is utilized to hold the main float control in on position until the pump loses suction. At the break suction point, the residual pressure in the volute immediately falls to its minimum value approximating zero in the region of the pressure tap-off so that the main float control is quickly released for rapid shut-off of the device without the necessity of a special calibration or adjustment to accommodate the static head condition of the particular installation. In the prior art, the pressure tapoff for pressure responsive control devices of this general character has been located in or immediately adjacent the discharge line from the pump so that the aforementioned difficulties are encountered.

Referring particularly to Fig. 2, the auxiliary control means comprises an extensible tubular rubber sleeve or boot, indicated generally at 36, with a pair of circumferential retainer rings 37 disposed exteriorly around the accordion pleated thin-walled body 38 thereof. The upper portion of the boot 36 has a relatively heavy or thick inwardly extending radial flange providing an end wall 39 with an aperture 41. An outwardly flanged annular retainer button 42 is permanently and rigidly secured, as by welding, to the underside of the diaphragm 18 so as to form an integral part of the diaphragm. The boot 36 is detachably connected to the diaphragm 13 by forcing the flanged button 42 into the opening 41 in the end wall of the boot so that the sump pump unit may be used with or without the auxiliary control device as desired. However, when the boot 36 is attached to the connector button 42,, it will readily be seen that the boot is in effect an integral part of the motor casing 14 and the end wall 39 is movable in unison therewith.

The opposite or lower end of the rubber boot 36 has a flanged open end with a relatively thick portion 43 extending radially outwardly and a thin flap-like portion 44 extending radially inwardly. The flanged end 43-44 is received in flatwise sealed relation against the inclined base 46 of a shallow cup-like retainer member 47 having an upright rim 4S and a central depending tubular extension 49. In the embodiment of the invention illustrated in Figs. 1-3 the tubular extension 49 has a press fit in an opening 51 in the upper wall, designated at 52, of the pump casing 8. As will best be seen in Fig. 3, the aperture 51 and the member 47 secured therein are located in the pump volute 1t) diametrically opposite or 180 from the discharge outlet pipe 11 and immediately above the outer periphery of the impeller 12. Thus, the boot 36 is disposed in the optimum location for minimum residual pressure in the pump volute at the break-suction point in accordance with the principles discussed heretofore.

Thus, the boot 36 when mounted on the bottom of the enclosure 14 is substantially integral with the enclosure by reason of the button fastener 42, and the lower end of the boot is merely removably seated in the retainer cup 47 and thus has no fixed attachment to the pump. As will be readily understood, the tubular body 38 of the boot 36 is axially extensible and collapsible to accommodate up and down movement of the motor enclosure 14 relative to the pump casing 8. As water under the volute pressure enters and fills the boot 36, it will be seen that the internal fluid pressure acting on the flange portions 39 and 44 will retain the opposite ends of the boot in sealed relation with the bottom of the diaphragm 18 and the retainer cup base 46, respectively. At the same time, the external fluid pressure due to the water level in the sump acts on the external flange portion 43 of the boot for holding the same in tight sealed relation in the cup 47. When the water level in the sump is relatively high such as to cause the float enclosure 14 to be lifted upwardly, thereby actuating the switch 29, the auxiliary control will have no particular eifect on the operation of the unit since the high water level in the sump is sufficient to maintain the pump in operation. However, as the water level in the sump recedes the float enclosure 14 tends to move downwardly, as described above, with the result that the switch 29 would eventually be shut off if there were no other force acting on the float 14. However, at this point the fluid pressure in the pump volute acting through the rubber boot 36 is imposed directly against the lower diaphragm element 18 and thereby urges the float 14 upwardly with sufficient force to insure continued operation of the pump until the water is completely exhausted from the vicinity of the pump inlet 9. When the pump loses suction and begins to draw air through the inlet 9, the fluid pressure within the boot 36 will immediately drop to its minimum value, as discussed above, and the float 14 will then drop rapidly to shut off the motor.

As a result of the combination of the main control means comprising the deflectable diaphragm and the auxiliary control means constituting the principal feature of the present invention, I am able to control the operation of the pump to insure that the sump is pumped to substantial dryness. The main control means functions primarily to reduce the water level in the sump to a certain minimum point and thereafter the float enclosure surrounding the pump motor is actuated by the auxiliary control means in response to the pressure of the liquid in the pump volute. Consequently, it may be said that the main control means functions in response to changes in liquid level in the sump, whereas the auxiliary control means functions independently of the liquid level in the sump. The foregoing results are accomplished with optimum effectiveness by reason of the favorable location of the auxiliary control pressure tap-off in the pump volute. Furthermore, the structure of the auxiliary control is highly simple and inexpensive and involves the use of only a single pressure responsive member, namely, the element 18 against which volute pressure is directly imposed by the auxiliary control device.

In Fig. 4, a modification of the invention is shown which is applicable when the vertical distance between the motor enclosure 14 and the pump casing 8 is some-, what greater than shown in Fig. 1. In such instances, a tubular member 53 is fitted in the opening 51 and the extension 49 on the cup 47 has a press fit in the upper end of the tube 53.

Although the invention has been described in connection with a certain specific structural embodiment, it will be understood that various modifications and equivalent structures may be resorted to without departing from the scope of the invention as defined in the appended claims.

I claim:

1. In a motor driven pump for emptying a sump or the like, a centrifugal pump having a casing with a volute and a discharge outlet from the volute, an impeller in said casing, an electric motor connected to said impeller for driving the same, main control means responsive to changes in liquid level in the sump for starting and stopping the motor, and auxiliary control means responsive to liquid pressure within the volute and cooperable with said main control means for maintaining the pump in operation until it loses suction, said auxiliary control means being connected to said volute solely at a location substantially diametrically opposite to said discharge outlet whereby said auxiliary control means is subjected to a minimum liquid pressure at the time the pump loses suction.

2. In a motor driven sump pump, a centrifugal pump having a casing with a volute and a discharge outlet from the volute, an impeller in said casing, an electric motor connected to said impeller for driving the same, an enclosure around said motor to render the same submersible, a control switch for said motor within said enclosure, said enclosure including diaphragm means disposed in operative relation with said switch and deflectable in response to changes in liquid level outside said enclosure for actuating said switch, and control means for imposing liquid pressure in said volute against said diaphragm means for maintaining said diaphragm means in switch-actuating position as long as liquid is being discharged from said pump unit, said control means being connected to said volute at a location substantially diametrically opposite to said discharge outlet whereby said liquid pressure is reduced to a minimum at the time the pump loses suction.

3. In a motor driven sump pump, a centrigual pump having a casing with a volute and a discharge outlet from the volute, an impeller in said casing, an electric motor connected to said impeller for driving the same, an enclosure around said motor to render the same submersible, a control switch for said motor within said enclosure, said enclosure including diaphragm means disposed in operative relation with said switch and deflectable in response to changes in liquid level outside said enclosure for actuating said switch, and control means for maintaining said diaphragm means in switch-actuating position independently of said liquid level whereby to insure operation of the pump until it loses suction and begins to draw air, said control means including means connected to said volute at a location substantially about from said discharge outlet for imposing the liquid pressure within the volute at said location against said diaphragm means when the pump is running full of liquid and for imposing the least possible pressure against said diaphragm means as soon as the pump loses suction and begins to draw air.

4. In a motor driven driven sump pump, a centrifugal pump having a casing with a volute and a discharge outlet from the volute, an impeller in said casing, an electric motor connected to said impeller for driving the same, a control switch for said motor, an enclosure around said motor to render the same submersible, main control means comprising a flexible diaphragm constituting an end portion of said enclosure and deflectable in response to changes in liquid level outside said enclosure for actuating said switch, and an auxiliary control comprising conduit means connected at one end thereof to said casing and communicating with said volute at a location substantially diametrically opposite to said discharge outlet, said conduit means having its opposite end disposed in engagement with said end portion of said enclosure for effecting deflection of said diaphragm in response to the pressure of the liquid in said volute at said location whereby to insure operation of the pump unit until the latter ceases to discharge liquid and whereby to obtain the maximum reduction in pressure in said conduit means when the pump loses suction.

5. In a motor driven sump pump, a centrifugal pump having a casing with a volute and a discharge outlet from the volute, an impeller in said casing, an electric motor connected to said impeller for driving the same, a hollow float chamber surrounding said motor to render the same submersible, said float chamber being supported on said motor for limited movement relative thereto, a control switch for said motor within said float chamber, said control switch being adapted to be actuated upon movement of said float chamber in response to changes in liquid level outside said float chamber, and conduit means connected to said volute at a location about 180 from said discharge outlet for imposing the pressure of the volute liquid at said location against the bottom portion of said float chamber whereby to lift the latter upwardly and thereby obtain continued operation of the pump as long as liquid is being discharged therefrom, said most remote location of said conduit means insuring a maximum reduction in liquid pressure in said conduit means when the pump loses suction.

6. Auxiliary control means for a motor driven sump pump having a pump unit including a casing with a discharge vo-lute, an electric motor, a control switch for the motor, and a motor enclosure including a deflectable diaphragm adapted to actuate said control switch, said control means comprising a flexible tubular conduit having openings at its opposite ends, and connector means adapted to be connected to the casing in fluid communication with the volute thereof and having a generally cupshaped portion in which one open end of said conduit is removably seated, the opposite open end of said conduit being adapted to receive a retainer mounted on the diaphragm for detachably connecting the conduit to the diaphragm in substantially sealed relation therewith whereby to impose liquid pressure in the volute through said conduit against said enclosure thereby deflecting said diaphragm and insuring continued operation of the pump unit until the latter loses suction, said flexible conduit having an extensibie portion intermediate the ends thereof for accommodating movement of the diaphragm relative to the pump casing.

7. The structure of claim 6 further characterized in that said conduit comprises a one-piece rubber tube having a radially flanged portion at said one end thereof adapted to seat in substantially fluid-tight relation in said cup-shaped portion, annular attaching means at said opposite end thereof adapted to coact with an annular retainer secured to the diaphragm, and a relatively thinwalled pleated portion intermediate said ends adapted to undergo elongation and collapsing in response to movement of the diaphragm relative to the pump caslng.

8 Auxiliary control means for a motor driven sump pump having a pump unit including a casing with a discharge volute, an electric motor, a control switch for the motor, and a motor enclosure including a deflectable diaphragm adapted to actuate said control switch, said control means comprising a flexible tubular conduit, an apertured end wall at one end of the conduit adapted to receive a connector element mounted on the diaphragm for sealingly connecting one end of the conduit to the diaphragm, radially extending flange means at the other end of said conduit, and a generally cup-shaped member having a tubular extension adapted to lit in an opening in the casing in fluid communication with the volute thereof, said flange means being adapted to seat in substantially fluid tight relation in the base of said cup-shaped member whereby liquid pressure in the volute is imposed through said conduit against said enclosure thereby deflecting the diaphragm and insuring continued operation of the pump unit until the latter loses suction, said conduit having an extensible portion intermediate the ends thereof for accommodating movement of the diaphragm relative to the pump casing.

9. The structure of claim 8 further characterized in that said radially extending flange means at said other end of said conduit has a thin inwardly extending portion adapted to be acted upon by fluid pressure within the conduit and a relatively thicker outwardly extending portion adapted to be acted upon by fluid pressure in the sump exteriorly of said conduit whereby the flange means is at all times retained in substantially fluid-tight seated relation with the base of said cup-shaped member.

10. In combination, a pump unit having a casing with a volute, said casing having an opening therein communicating with the volute, an electric motor mounted on and operatively connected to the pump unit, a control switch for the motor, a motor enclosure for rendering the motor submersible and including a deflectable diaphragm adapted to actuate the control switch, and control means including a flexible tubular conduit sealingly connected at one end thereof to said volute at said opening, an annular retainer element rigidly mounted on said diaphragm, and resilient connector means at the other end of said conduit for detachably connecting the latter to said retainer element in substantially fluid tight relation with said diaphragm whereby to transmit liquid pressure from the volute through said conduit against said diaphragm and thereby deflecting the latter and insuring continued operation of the pump unit until the latter loses suction, said conduit having an axially extensible and collapsible portion intermediate its ends for accommodating movement of said diaphragm relative to said casing.

11. In combination, a pump unit having a casing with a volute, said casing having an opening therein communicating with the volute, an electric motor mounted on and operatively connected to the pump unit, a control switch for the motor, a motor enclosure for rendering the motor submersible and including a deflectable diaphragm adapted to actuate the control switch, and control means including a flexible tubular conduit having a flange at one end thereof, a cup-shaped connector mounted on said casing in fluid communication with said volute at said opening, said flange being received in flatwise fluid-tight seated relation at the base of said connector, a retainer element rigidly mounted on said diaphragm, and an apertured end wall at the other end of said conduit for receiving and detachably connecting the latter to said retainer element in substantially fluid-tight relation with said diaphragm whereby to transmit liquid pressure from the volute through said conduit against said diaphragm and thereby deflecting the latter and insuring continued operation the pump unit until the latter loses suction, said conduit havi g an axially extensible and collapsible portion intermediate its ends for accommodating movement of said diaphragm relative to said casing.

12. The structure of claim 10 further characterized in 9 that said pump unit has a discharge outlet from said volute and said opening in the casing is located substantially diametrically opposite said discharge outlet so as to obtain rapid reduction of fluid pressure in said conduit to a minimum when the pump loses suction.

UNITED STATES PATENTS Hicks Jan. 15, 1918 Horter June 28, 1927 Morgan July 22, 1941 Schaefer Jan. 13, 1953 

